Portable electronic devices permeate everyday life in modern technological society. From portable information management systems to portable entertainment systems, the demand for new devices having more robust features and reliability continues to grow. One area that is critical to the success of an innovative electronic device is electronic display configuration and management. As may be appreciated, electronic displays utilized in portable electronic devices may be subject to a variety of environmental factors such as ambient light extremes, which may adversely affect a user's viewing experience. For example, when an electronic device is carried from indoors to direct sunlight, the devices electronic display may be too dark to read until the display compensates for the ambient light change. Conversely, when an electronic device is carried from direct sunlight to indoors, the device's electronic display may be too bright to view until the display compensates for the ambient light change.
To address this problem, some electronic devices utilize an ambient light sensor in combination with an electronic display. The purpose of an ambient light sensor is to sense ambient light intensity. Sensed ambient light intensity generates data that may then be used to adjust electronic display brightness. FIG. 1 is a graphical representation of a prior art backlight control curve graph. As may be appreciated, backlight control may be utilized with an electronic display to adjust backlight levels (i.e. brightness). As illustrated, a backlight control curve is graphed with respect to backlight level 110 and ambient light intensity 120. In this example, a minimum backlight start level 102 may be utilized for a low ambient light intensity. Point 104 represents a stepped increase in backlight level over a range of ambient light intensity. Point 106 represents a maximum backlight level available for a particular ambient light level. Point 108 represents a point at which ambient light intensity is high enough that the electronic display no longer benefits from backlight, at which point backlight level is reduced to zero (i.e. backlight is switched to OFF). As may be appreciated, a stepped increase in backlight level may provide at least some response to changing ambient light conditions. However, this technique represents a compromise. That is, the coarse granularity in backlight control often results in a backlight level that is too high or too low for a given ambient light condition. A finer granularity of backlight control may provide backlight levels that more closely match an ambient light condition and thus, may enhance a user's viewing experience.
In some conventional electronic devices, an ambient light sensor may be isolated from the devices electronic display in order to avoid stray light emissions from the display. However, in other electronic devices, an ambient light sensor may be co-located with the device's electronic display in order to achieve, for example, a smaller form factor. In those examples, light emissions from the electronic display may interfere with the ambient light sensor. Thus, for example, ambient light intensity may be incorrectly read as too high because of contributing stray light emissions from the electronic display resulting in an inaccurate backlight level. As such, it may be advantageous to eliminate stray light emissions while an ambient light sensor is operating.
Therefore, dynamic backlight control systems are presented herein.